In this additional component of a study by Merck (L-735,524 plus ZDV plus 3TC vs ZDV plus 3TC in HIV infection) the investigators will determine how rapidly HIV levels can fall and how rapidly CD4 cell numbers can increase if the destruction of these cells is greatly decreased with therapy. The study will reveal valuable information on the relative decreases in serum HIV, cells expressing HIV, and latently infected cells, and increases in new CD4 cells.